As computer systems and software become more interconnected, e.g. hardware connection through networks and software connection through portability of computer programs and data, it becomes increasingly difficult to ensure the security of the computer system from unauthorized intrusions, by unauthorized users and unauthorized alterations, such as by viruses. Furthermore, as computers become more interconnected, it becomes more difficult to isolate the intrusion once an intrusion has occurred at one node of a computer network.
Virus detection programs are well known in the art. In a typical prior art virus detection program, the program seeks to determine the existence of a particular virus residing within the storage subcomponent (memory or disk) of a computer. However, such prior art anti-viral programs detect only a priori known viruses. If a new virus were developed and introduced into the computer program, with the anti-viral program not being able to identity the new virus, the anti-viral program would be unable to detect the existence of the newly introduced virus. Therefore, one of the short comings of the anti-viral programs of the prior art is that the anti-viral programs must be constantly updated to identify newly created viruses.
Similarly, another problem with the prior art anti-viral programs is that once a virus has "infected" one node of a computer on a network, and if the anti-viral program is unable to detect it, and if the same anti-viral program is residing on all of the other computers on the network, then the virus can spread undetected to all the other computers on the network. The result is that any new virus which can intrude into a node on a computer network, is virtually assured that it can spread and intrude into the entire computer network.
In the computer arts, programs that compare one file to another file to detect changes therein, similar to anti-viral programs, are also well known. In addition, file authentication methods, such as checksum, or the like are also well known in the art.
In the field of biology, immune system cells are well known in the art. T cells are part of the immune system. T cells have receptors on their surfaces that can detect antigens. These receptors are made by a pseudo-random genetic process and it is highly likely that some receptors will detect molecules from the body or "self molecules". T cells undergo a censoring process in the thymus called negative selection. In negative selection, T cells that recognize self molecules or molecules that are normal to the body, and in particular the molecules being peptides, are destroyed and are not allowed to leave the thymus. The T cells that do not detect self peptides leave the thymus and provide one basis for the immune protection against foreign antigens.